She spent much of her childhood watching television and old Hollywood movies, from which she learned to impersonate her favorite actresses, such as Joan Bennett and Kim Novak. In 1961, she signed up for a course at the DeVern School of Cosmetology in Baldwin, Long Island. Darling later said that she "learned about the mysteries of sex from a salesman in a local children's shoe store" and finally revealed an inclination towards cross-dressing when her mother confronted her about local rumors, which described Darling as "dressing as a girl" and frequenting a local gay bar called The Hayloft. In response, Darling left the room and returned in feminine clothing. Darling's mother would later say that, "I knew then... that I couldn't stop Jimmy. Candy was just too beautiful and talented."
Darling first took the name Hope Slattery. According to Bob Colacello, Darling took this name in 1963/1964 after she started going to gay bars in Manhattan and visiting a Doctor on Fifth Avenue for hormone injections. Jackie Curtis said that Darling adopted the name from a well-known Off-Off-Broadway Actress named Hope Stansbury, with whom she lived for a few months in an apartment behind the Caffe Cino. Holly Woodlawn remembers that Darling's name evolved from Hope Dahl to Candy Dahl, then to Candy Cane. Jeremiah Newton said she took the name "Candy" out of a love for sweets. In her autobiography, Woodlawn recalled that Darling had adopted the name because a friend of hers called her "darling" so often that it finally stuck.
Darling met Jeremiah Newton in the summer of 1966, when Newton was on his first trip to Greenwich Village from his home in Flushing, Queens. The two became friends and roommates, living together in Manhattan and Brooklyn until the time of Darling's death in 1974.
Her theatre credits include two Jackie Curtis plays, Glamour, Glory and Gold (1967) and Vain Victory: The Vicissitudes of the Damned (1971). Vain Victory was directed by Curtis at La MaMa Experimental Theatre Club in May/June 1971, and featured many other performers from Warhol's Factory, including Curtis, Ondine, Tally Brown, Mario Montez, Samuel Adams Green, Mary Woronov, Francesco Scavullo, Jay Johnson (twin brother of Jed Johnson), Holly Woodlawn, Steina and Woody Vasulka, Eric Emerson, and Warhol himself.
Warhol cast Darling in a short comedic scene in Flesh (1968) with Jackie Curtis and Joe Dallesandro. After Flesh, Darling was cast in a central role in Women in Revolt (1971). She played a Long Island socialite, drawn into a woman's liberation group called P.I.G.S. (Politically Involved Girls) by a character played by Curtis. Interrupted by cast disputes encouraged by Warhol, Women in Revolt took longer to film than Flesh and went through several title changes before it was released. Darling wanted it called "Blonde on a Bum Trip", since she was the blonde, while Curtis and Woodlawn told her it was more like "Bum on a Blonde Trip".
Darling went on to appear in other independent films, including Silent Night, Bloody Night, Wynn Chamberlain's Brand X, and a co-starring role in Some of My Best Friends Are... She appeared in Klute with Jane Fonda and Lady Liberty with Sophia Loren. In 1971, she went to Vienna to make two films with Director Werner Schroeter:The Death of Maria Malibran, and another film that was never released. Darling's attempt at breaking into mainstream movies, by campaigning for the leading role in Myra Breckinridge (1970), led to rejection and bitterness.
Darling was in the original 1972 production of Tennessee Williams' play Small Craft Warnings, cast at Williams' request. She starred in the 1973 revival of The White Whore and the Bit Player, a 1964 play by Tom Eyen, at La MaMa Experimental Theatre Club. The production was bilingual, called The White Whore and the Bit Player/La Estrelle y La Monja, and directed by Manuel Martin, Jr. Darling's character, a Hollywood Actress known only as "the Whore", was based on Marilyn Monroe. She performed in the English version opposite Hortensia Colorado, and the Spanish version was performed by Magaly Alabau and Graciela Mas. As a review of the play stated, "With her teased platinum hair and practiced pouts, Miss Darling looks like her character and resolutely keeps her acting little-girl-lost. The role-playing aspect works to her advantage. She could, after all, be a male lunatic pretending to be the White Whore."
Darling died of lymphoma on March 21, 1974, aged 29, at the Columbia University Medical Center division of the Cabrini Health Center. In a letter written on her deathbed and intended for Warhol and his followers, Darling wrote, "Unfortunately before my death I had no Desire left for life ... I am just so bored by everything. You might say bored to death. Did you know I couldn't last. I always knew it. I wish I could meet you all again."
A feature-length documentary on Darling, titled Beautiful Darling, premiered at the Berlin International Film Festival (or Berlinale) in February 2010. The documentary features archival film and video footage, photographs, personal papers, archival audio interviews with Tennessee Williams, Valerie Solanas, Jackie Curtis and Darling's mother, as well as contemporary interviews with Holly Woodlawn, Fran Lebowitz, John Waters, Julie Newmar, Peter Beard, and Taylor Mead. Chloë Sevigny narrates the film, voicing Darling's private diary entries and personal letters. The film was directed by James Rasin and produced by Jeremiah Newton and Elisabeth Bentley.
The day after the Celebrity preview, a group of women carrying protest signs demonstrated outside the cinema against the film, which they thought was anti-women's liberation. When Darling heard about this, she said, "Who do these dykes think they are anyway? Well, I just hope they all read Vincent Canby's review in today's Times. He said I look like a cross between Kim Novak and Pat Nixon. It's true – I do have Pat Nixon's nose."
